A bushing is configured by a central conductor penetrating through the inside of a porcelain tube made of, for example, porcelain or polymer (for example, see Patent Literature 1).
Further, in a gas circuit breaker to which a bushing is connected, an end portion of the central conductor is inserted into an insertion portion provided in an arc-extinguishing chamber in a circuit breaker tank, and the bushing is thus electrically connected to the gas circuit breaker.